Lead-supply system for pig-casting machines.



J. F. MILLER.

LEAD SUPPLY SYSTEM FOR PIG CASTING MACHINES.

APPLICATION FlLED SEPT-26,1916.

Patented Jan. 29, 1918 llll 5] nuewfoz 351g 61am 6, 62%. a

JOHN F. MILLER, OF TRAIL, BRITISH COLUMBIA, CANADA.

LEAD-SUPPLY SYSTEM FOR PIG-CASTING MACHINE S.

Specification of Letters Patent.

Patented Jan. 29, 1918.

Application filed September 26, 1916. Serial No. 122,187.

To all whom it may concern Be it known'that I, JOHN F. MILLER, a citizenof the United States, residing at Trail, British Columbia, Dominion ofCanada, have invented certain new and useful Improvements in Lead-SupplySystemsfor Pig-Casting Machines, of which the following-is a full,clear, and exact description.

In the use of machines for casting lead pigs it is desirable that thetemperature of the molten lead be kept as little above the melting pointas possible, not only to economize the fuel used in melting the bullionbut also to keep down the heat absorption necessary to solidify the leadin the molds. Moreover, lead does not expand, as does iron, butcontracts in passing from the molten to the solid state, and hence thenearer the molten metal is to the melting point the less does itcontract in the mold. On the other hand if the temperature is :too low,the metal is very apt to freeze at the outlet of the pipe .by which itis delivered to the molds, thereby necessitating thawing the pipe outbefore the casting can proceed. This is a not uncommon occurrence unlessgreat care is exercisecl, especially when the operation is be- I gun andthe machine is cold.

' the metal cools (and contracts) the space I have accordingly been ledto devise my present invention, which has .for its chief object toprovide a lead-supply system by which freezing is minimized and any leadthat solidifies at the outlet of the supply pipe will be quickly melted.Another object is to provide a supply system in which a static head willbe maintained against the molten metal in each mold as it is. filled, sothat as thus formed will be filled with additional metal therebyinsuring pigs of uniform size. To these and other ends the inventionconsists in the novel features and combinations hereinafter described.

One form of the invention is illustrated in the accompanying drawings,in which the same is shown in side elevation, partly in section.

In the apparatus illustrated, 10 is a portion of the rim of therevolving vertical mold-wheel, having outwardly open pigmolds 11 on itsperiphery and an inner water-jacket or backing12. On the outside is astationary arc-shaped water-'aclzet 13, of suitable circumferentialextent gsay about 100) to close the molds as they pass. .In'

its lower portion the outer jacket is formed with a depression 14, andthrough this depression the lead supply pipe 15 extends intocommunication with the molds. The purpose of this depression is todiminish the cooling eflect of the jacket on the supply 'pipe. No claimis made herein to this feature per 86, as it-is claimed broadly-in'mypsior Patent No. 1,157,794, dated October 26,

15. The supply pipe 15, which is connected with a suitable. pump (notshown) for delivering molten lead, includes a T 16, in the outer end ofwhich is screwed a bushing 17 having a threaded central aperture toreceive a short length of externally threaded pipe 18. The latterextends toward the inner end of the T and at its inner end carries ashort intake pipe 19. This pipe terminates close to the orifice of thelead-supply pipe 75. 15 and its inlet orifice is beveled at an angle ofabout 45 on. the underside, as shown. The outer end of the connectingpipe 18 is screwed into a bushing 20 (like bushing 17 in the lower endof a lead-return pipe 21 which leads back to the source of molten lead,notshown. This return pipe is arched a slight distance above the top ofthe supply pipe 15, as shown.

' will be speedily melted again by the stream of hot metal flowingaround and into the pipe 19, thus making it unnecessary to dismantlesystem or have recourse to a torch or otherlexternal source of-heat;unless of course, the metal should congeal back to the vertical portionof the supply pipe and choke the same. -In such case (which will notoccur if ordinary care andintelligence are used the outlet can be thawedoutby means 0 a blow-torch flame applied to the outside of the pipe. Thebeveling of the end of tube 19 is of advantage in that it enlarges thearea of the orifice, making-it less liable to freeze over, and carriesthe orifice back farther while keeping the end of the pipe near theorifice of the supply pipe. 4

As the casting continues the excess-metal delivered by the supply pipeaccumulates in the short leg of the return pipe and soon overflowsthrough the bend and into the depending leg. There now exists on themetal flowing into the molds a constant head equal to the height of thereturn bend above the outlet of the supply pipe. Hence, as the metal inthe mold cools and contracts (contraction begins as soon as the moltenmetal strikes the relatively cool walls of the mold) additional metal isforced in at a pressure that is constant by reason of the constantheight of metal in the return bend. This pressure is exerted on eachindividual mold from the time when it first reaches the supply pipeuntil it leaves it, and the mold is therefore full at the instant it isentirely past the pipe. By this time the metal, while perhaps notsolidified, is cooled down near to the point of solidification. By thattime most of the contraction has occurred, leaving very little to takeplace afterward. The result is that the contraction after the mold isfilled is scarcely appreciable, thus giving pigs that are smooth andclean on all surfaces.

lit isto be understood that the invention is not limited to theconstruction herein specifically illustrated and described but can beembodled in other forms without departure from its spirit.

I claim: 1. In a machine for casting lead pigs, the combination with amold wheel provided with open molds on its periphery, of an outerarc-shaped member fitting the periphery to close the molds as they pass,a supply pipe extending through said member to deliver molten lead tothe molds, and a rethey pass, a supply pipe extending throughsaid memberto deliver molten lead to the molds, an intake tube of relatively smalldiameter inside the supply pipe, arranged with itspinlet orificeadjacent to the outlet orifice of the supply pipe, to receive excessmetal, and areturn plpe connected to the other end of the intake tubefor carrying ofi' the excess metal.

3. In a machine for casting lead pigs, the combination with a revolvingmold wheel having a plurality of open molds on its periphery, of anarc-shaped member fitting said periphery to close the molds as theypass, a supply pipe extending through said member to deliver molten leadto the molds, a return pipe arched above the supply pipe, and an intaketube of relatively small diameter extending from the return pipe intothe supply pipe and terminating adjacent to the outlet orifice of thelatter.

Tn testimony whereof ll hereunto affix my signature.

JOHN F. MILLER.

